I think what SdJ represents doesn’t really equate to “this is the best game” so much as “this is a game that you should pick up and play over Christmas” because of the criteria that is involved in selection.

Oh absolutely. I own several SdJ winners such as MicroMacro, Just One, Azul, Codenames, Ticket to Ride.... They're great games to play with the family and most of the times they're big hits.

Their advanced category is effectively “ok, you’ve already played a couple of boardgames, now here is the next level” which is still a far cry from Terra Mystica

This is where I believe they often (not always) fail. If Challengers was in the Spiel des Jahres category no one would have thought it was odd because they're at the same level. The next level should be something around the 2.5 weight category. Even though I don't personally enjoy Wingspan, I think it was a great choice for a next level kind of game.

Good candidates for 2022, though I'm not sure they have a german version, would be Heat: Pedal to the Metal, Flamecraft, Turing Machine, Caper: Europe...